1. Field of the Invention
The present invention relates to a method and an apparatus for automatically sterilizing bacteria in a hospital, and more particularly to the method and the apparatus for effectively sterilizing bacteria by spraying disinfectant so as to prevent the occurrence of an infection caused by bacteria floating in an operation room, a ward or the like of a hospital or bacteria which have stuck to walls or floors of the hospital. The method and apparatus can also be used in equipment such as in a food manufacturing factory requiring sterilization.
2. Description of the Related Art
Recently, hospital infection has been remarkably increasing. When babies, old people or people suffering from disease having a weak resistance to bacteria become infected with Pseudomonas aeruginosa or MRSA (Methicillin Resistant Staphylococcus aureus) having multiple drug resistance to antibiotics, bacteria increase in their bodies, thus causing pneumonia, enteritis, suppuration of skin or septicemia.
Since MRSA is resistant to antibacterial agents in addition to antibiotics, research is being conducted to develop medicine or methods for sterilizing MRSA. In this situation, it is necessary to sterilize bacteria in hospitals so as to prevent people from being infected with MRSA or the like.
MRSA grows in the highest degree in operating rooms. According to a sampling inspection carried out recently, positive MRSA was 0 to 3% in wards for internal treatment while it was as high as 20% in wards for surgical treatment.
It is therefore absolutely necessary to completely sterilize bacteria in operating rooms to prevent the hospital infection. MRSA of a patient may be infected via a patient's bed, clothes of doctors, nurses, or workers, air-conditioning equipments or medical instruments not sterilized sufficiently. Accordingly, it is also necessary to sterilize places in which MRSA is likely to grow in addition to operating rooms.
It is necessary to sterilize bacteria which have stuck to floors, walls, ceilings, beds, shelves, medical equipments and those floating in the air.
Mops on which disinfectant has been put are mainly used to wipe floors or the like to sterilize bacteria which have stuck thereto. Bacteria floating in the air is sterilized by disinfectant which is scattered or sprayed; gas fumigation; ultraviolet rays irradiated to floors or the like; or filters of air-conditioning equipment.
The above-described sterilizing methods have the following problems:
1. A sterilizing method which uses a mop for cleaning has a problem in that the mop may not be clean. Since mops are made of cotton, bacteria tend to stick thereto. For example, approximately as many as 50,000 to 100,000 bacteria stick thereto per one inch. That is, mops may scatter bacteria over a large area.
It is difficult to adjust the concentration of disinfectant to be provided to the mop to an appropriate value. In addition, an excessive amount of disinfectant may be contained in the mop and thus disinfectant may not be applied uniformly to floors or the like.
Further, it often occurs that a high place or the back surface of a shelf or the like is not wiped with the mop. In addition, a sterilizing method is also required to sterilize bacteria floating in the air.
2. In the sterilization by means of gas fumigation to be carried out with a room air-tight, the room smells of gas for a few days after the room is fumigated.
3. In the sterilization by means of ultraviolet rays, portions of the room shaded from the ultra-violet rays cannot be sterilized. The sterilizing effect decreases in proportion to the square of the distance between an object and a light source. Thus, floors, ceilings or the like cannot be uniformly sterilized. Further, resin or products made of rubber will tend to deteriorate.
4. In the sterilization by means of the filter of air-conditioning equipment, bacteria floating in the air can be caught but bacteria which have stuck to floors or the like cannot be sterilized. Therefore, an additional sterilizing method is also required to sterilize bacteria stuck to floors or the like. Moreover, it is necessary to replace the filter often.
5. The method of scattering or spraying disinfectant is the most effective because the method is capable of sterilizing bacteria floating in the air and bacteria which have stuck to floors and the like.
The method has, however, a problem that large-diameter particles of disinfectant drop to the floor before they sterilize bacteria floating in the air, hence causing a decrease in the sterilizing effect of the disinfectant.
It is necessary to uniformly spray disinfectant in all directions in the room. It takes much time to spray disinfectant manually. In addition, a person in charge may be infected with bacteria while the person is spraying the disinfectant. In addition, there is a great possibility that ill effects will be produced.